文档介绍：第一章1-13mkg/-20273273tkg/-3V1dtdVVt21t1V2V1V13/hVVm62(tt)VV55010(8020)-463dp1/1dV1VV199510110VppV210101102**********Pa1-54Pa·-62/-7(1)um/.(2)MFd2Adudyd2dLdudyd22MPa·(3)-8(1)dudy2y(2)dudy2y2121-9(1)F2Adudy2bLu0h(2)当hy时,2duu0dyh(3)当y3时,h2duu所以0u0dy1-10FNFF(12)··-11dArrrdrrrdrdu02dMdFr2dysinsinMHtg0dMHtg02rsin3dr2sinHtg0r3dr2(Htgsin24)44Htgcos31-12um/-·-14dMdFrdAdudyr2rdrr02rr3drMdMAd202r3ddr3241--..-·-18由1-14的结果得42nd4424MN·-%1--21hHgm()()-22由hg3422R2R62得gh23R226R42其中1sinRcos则2gRh2Rcos1312sinsin21-23根据牛顿内摩擦定律dVdr由于流速u随半径r的增加而减小,即du是负值,为了使为正值,上式在等号dr右端取负号2dD根据已知条件rr2[()]dr442在管壁处Dr则212D2D4当D22D2D4r时4管壁处的阻力FADDLDL121441-24mG90(kg)().·--2pvp(0gh)**********.-(a)pe()**********e(b)pe()(c)pe()gh(136001000)**********e2-